3-Dimension Fiber Structures for Composites and Interfaces

ABSTRACT

A material suitable to keep layers or plies of a composite material from adhering to each other during production and transportion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and is a Divisional of, U.S. patentapplication Ser. No. 12/870,580, filed on Aug. 27, 2010, now allowed,which claims priority from U.S. Provisional Application No. 61/275,397,filed on Aug. 28, 2009, both of which are hereby incorporated byreference in their entirety.

FIELD OF INVENTION

The subject invention relates to the art of composite materials, andmore particularly, to 3-Dimention fiber structure for composite andinterfaces.

BACKGROUND OF THE INVENTION

Fiber composite materials have been used in a wide range of industries(e.g., aerospace, aviation, automobile, ship, construction, sportsequipment, etc.) for several decades. Fiber composite materials aregenerally manufactured through a process where fiber products are laidup filaments by filament, ply by ply, and layer by layer, then bondedtogether using materials, such as plastics, rubber, metal, or othernon-metal materials. A connection interface exists between twofilaments/plies/layers. Fiber composite materials are usually weak atconnection interfaces or inter-laminate area. For example, tensilestrength of fibers within a ply can be higher than 3000 MPa (MegaPascal), much higher than that of common steel; but interface orinter-laminate strength of fiber composite material is usually about 100MPa, even lower than that of aluminum. Thus, the interface orinter-laminate strength of fiber composite material is only about 1/30of the tensile strength of fiber themselves.

It is generally difficult and expensive to increase the interface orinter-laminate strength of the fiber composite material by using astronger bonding material (e.g., adhesives, plastics, or resin, etc.).The lower interface or inter-laminate interface strength of compositesoften leads to structural failures, such as de-lamination and de-bondingunder conditions such as stress, impact, or fatigue. Therefore, adoptionof fiber composite materials, especially in load-bearing structures, hasbeen limited by their susceptibility to out-of-plane failures caused bylow interface or inter-laminate strength. To alleviate these problems,methods of trans-laminate and cross-interface reinforcements, such as3-D stitching, 3-D weaving, 3-D knitting, or 3-D braiding, have beenused to improve de-lamination resistance and enhance interface strength.These 3-D reinforcement techniques, however, demand sophisticatedequipments and require complicated manufacturing processes, andtherefore, prolong the manufacture process, drive up the manufacturecost, and lower the manufacture productivity.

SUMMARY OF THE INVENTION

In general, in an aspect, the invention provides a sheet article, thesheet article including a substrate, a plurality of fasteners on atleast a portion of one surface of the substrate, and a cover, at leastpartially covering the plurality of fasteners, wherein the cover atleast partially protects the plurality of fasteners and prevents theplurality of fasteners from engaging other fasteners or pressing downand wherein the covered fasteners can be exposed and the cover can beremoved if needed.

Implementations of the invention may provide one or more of thefollowing features. The plurality of fasteners are selected from a groupcomprising of hooks, loops, anchor-shape hooks, fish hooks, forks, bigheads, arrow-shape hooks, group loops, and group hooks. The coverincludes a second substrate, a plurality of upstanding or protrudingstuds or walls on the second substrate, wherein the plurality ofupstanding or protruding studs or walls protect a plurality of fastenerson an adjacent sheet. The hook or loop shape hook is stiffened to acertain level so that it can engage with other hook or loop fasteners onother sheet articles. In order to stack up the sheet articles, thecovers are only on the designed parts of the designed sheet (e.g., adesigned part on the surface sheet), laid up at least three plies of thesheet articles to form a 3D composite, wherein all plies may be fastenedby the engaged fasteners on the piles, wherein matrix material is usedto bond the at least three plies, wherein surface side may or may nothave fasteners, wherein surface side may or may not have covers at thedesigned part. The sheet article is impregnated with one or more matrixmaterials selected from the group of polymer, resin, metal, ceramic,carbon, or glass to obtain a prepreg sheet, laid up at least two saidprepreg plies to get a 3D composite, wherein only surface side may ormay not have covers at the designed part.

Implementations of the invention may also provide one or more of thefollowing features. In order to increase the bonding strength of twoarticles, the cover is removed; insert the sheet article to theinterface area of two articles when bonding the two articles, whereinthe fasteners on the sheet article will extend into the bodies of twobonding articles to increase interface strength, wherein the fastenerson the sheet article will interlock with the fasteners of two bondingarticles if they have fasteners themselves. The substrate is made ofplurality of fiber sheet plied contiguously, wherein the plurality fibersheet are mechanically fastened together. The fibers in the same sheetcan be lined up at the same direction or at different directions forminga multi-layer, multi-axis sheet. In order to stack up the sheetarticles, the covers are only on the designed parts of the designedsheet (e.g., a designed part on the surface sheet), laid up at least twoplies of the sheet articles to form a 3D composite, wherein all pliesmay be connected and supported by the fasteners on said piles, whereinmatrix material infiltrates at least partial of the plies and fasteners,wherein said plies are not fully touched and there are hollow spacesbetween plies, wherein surface side may or may not have fasteners,wherein surface side may or may not have covers at the designed part.The sheet articles have gap between two sheet articles to fit pins offiber sheet handling tool, wherein pins can grab and separate the sheetarticle. The fasteners can lean with acute angle at desired location anddirection. The substrates have matrix material at inner walls ofopenings, wherein fasteners can be aligned through openings.

In general, in another aspect, the invention provides a method of usingfastener cover on a sheet, including the steps of applying a coveringmaterial to at least one fastener on the sheet to protect the at leastone fastener and removing the cover material during a bonding process toexpose the at least one fastener.

Implementations of the invention may provide one or more of thefollowing features. The method further includes the step of applying asizing or a coating material to coat the at least one fastener.

In general, in yet another aspect, the invention provides a tool forhandling a sheet with fasteners, including a base, a connector, capableof being coupled to a driving force, a housing unit in the base, amoving element, positioned at least partially within the housing unitand coupled to the driving force, and a plurality of fasteners on atleast a portion of one surface of the moving element.

Implementations of the invention may provide one or more of thefollowing features. The moving element can be fully hidden in thehousing unit in the base and can extend out of the housing unit. Aplurality of fasteners exist on at least a portion of one surface of thebase if they are not on the moving element.

In general, in still another aspect, the invention provides a tire orcutting wheel, including a plurality of sheets and a plurality offasteners on at least one of the plurality of sheets, wherein theplurality of fasteners on adjacent sheets are interlocked.

Implementations of the invention may provide one or more of thefollowing features. The plurality of fasteners in the cutting wheelwithhold particles against wearing during cutting.

These and other capabilities of the invention, along with the inventionitself, will be more fully understood after a review of the followingfigures, detailed description, and claims.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates an exemplary sheet of fibers or substrate withfasteners on its both sides.

FIG. 2 illustrates an exemplary composite made of fiber sheets withfasteners.

FIG. 3 illustrates an exemplary 3-D prepreg sheet with fasteners on itsboth sides.

FIG. 4 shows a cross-section view of the 3-D prepreg sheet of FIG. 3.

FIG. 5 illustrates an exemplary method of generating fasteners.

FIG. 6A shows a cross-section view of another exemplary sheet.

FIG. 6B shows a top view of the sheet in FIG. 6A.

FIG. 7A shows a cross-section view of another exemplary sheet with afiber mat as an additional layer.

FIG. 7B shows a top view of the sheet in FIG. 7A.

FIG. 8 illustrates an exemplary multi-layer multi-axis sheet.

FIG. 9A shows a cross-section view of an exemplary multi-layermulti-axis prepreg sheet with a matrix material.

FIG. 9B shows a top view of the multi-axial prepreg sheet of FIG. 9A.

FIG. 10A shows a cross-section view of a first article with fastenersand a cover.

FIG. 10B shows a cross-section view of a second article with fastenersand a cover.

FIG. 11A shows a cross-section view of the first article of FIG. 10Awith the cover removed.

FIG. 11B shows a cross-section view of the second article of FIG. 10Bwith the cover removed.

FIG. 12 shows a cross-section view of the two fiber articles of FIG. 11Aand 11B interlocked together by the fasteners on both fiber sheets.

FIG. 13A shows a cross-section view of a first article withoutfasteners.

FIG. 13B shows a cross-section view of a second article withoutfasteners.

FIG. 13C shows a cross-section view of an exemplary fiber sheet withfasteners on both sides.

FIG. 13D shows a cross-section view of the two articles of FIG. 13A and13B interlocked together by the fasteners of the fiber sheet of FIG.13C.

FIG. 13E shows a cross-section of view of two articles with fastenersinterlocked together using the fiber sheet of FIG. 13C.

FIG. 14A illustrates a sheet with extension studs and windows.

FIG. 14B shows a cross-section view of the sheet of FIG. 14A beingplaced between two sheets with fasteners.

FIG. 14C shows a cross-section view of the sheet of FIG. 14A beingplaced within a roll of sheets with fasteners.

FIG. 15A illustrates an exemplary fiber-sheet handling tool.

FIG. 15B illustrates another exemplary fiber-sheet handling tool.

FIG. 15C illustrates yet another exemplary fiber-sheet handling tool.

FIG. 16A illustrates a cutting wheel made of multiple fiber sheets.

FIG. 16B shows a cross-section view of the cutting wheel of FIG. 16A.

FIG. 17A illustrates an exemplary sheet with fasteners of differentlength and stiffness on two sides.

FIG. 17B illustrates two sheets of FIG. 17A interlocked together byfasteners of different length and stiffness.

FIG. 17C shows a close-up cross-section view of the sheet of FIG. 17A.

FIG. 18A shows a cross-section view of an exemplary sheet with openings.

FIG. 18B shows a cross-section view of the sheet of FIG. 18A coupledwith a stopping plate or film.

FIG. 19A and FIG. 19B are photos of a prototype showing fasteners withacute angle engaged and interlocked.

FIG. 20A illustrates an exemplary tire that can be at least partiallymade of fiber sheet with fasteners.

FIG. 20B shows a cross-section view of a portion of the tire of FIG.20A.

FIG. 21 illustrates an exemplary composite panel or block.

DETAILED DESCRIPTION

Embodiments of the invention provide apparatuses and methods forimproving inter-laminate and interface strength of composites.Trans-laminate and cross-interface reinforcements, such as fasteners, onthe fiber sheets are configured to engage and interlock to providetrans-laminate and cross-interface reinforcement. These techniquesutilize traditional textile industry technologies, non-weavingtechnologies, and hook and loop (e.g., Velcro) technologies, and arecompatible with traditional low cost 2-D manufacturing process. Thetrans-laminate and cross-interface reinforcements help to increaseimpact and wearing resistance, improve thermal and/or electricalconductivity, enhance fatigue durability, extend usage life, advancemanufacturability of composites, and expand applications of composite.

Referring now to FIG. 1, an exemplary sheet of fibers or substrate 10has fasteners 29 on both sides of the sheet or substrate. The fastenerscan be in the form of hooks 11, loops 12, anchor-shape hooks 13, fishhooks 14, forks 17 and 21, big heads 18, arrow-shape hooks 19, grouploops 20, or group hooks 15 and 16. The group hooks 15 or 16 can includemultiple hooks to form chains of hook strings. The hooks 11, 13, 14, 15,16, or 19 can include multiple threads 22 in different lengths. Thefasteners 29 can form a pattern. One example of patterns is an array onthe sheet or substrate 10 with specified directions. The fasteners 29can also be randomly scattered or mixed on the sheet or substrate 10.The sheet or the substrate 10 can include multiple plies 101 and 102.The terms “ply” and “sheet” can be used to describe different physicalstructures, including but not limited to, thread, filament, strand,yarn, layer, or multiple plies formed as one ply/sheet.

As illustrated in FIG. 2, several sheets or substrates 10 are laidtogether layer-by layer to form a composite preform 30. The fasteners(e.g., hooks and loops) can be configured to engage each other toprovide trans-layer, inter-layer, and interface reinforcements. Thetrans-layer fasteners make composite preform 30 a 3-D composite.Preferably, the top sheet and the bottom sheet have fasteners only onthe inner side (i.e., the side facing an adjacent sheet) of the sheets.As discussed above, the sheet or the substrate 10 can include multipleplies 101 and 102.

In one embodiment, the multiple-ply sheet 10 is a sheet of prepreginfiltrated with a polymer matrix (e.g., epoxy or resin). FIG. 3illustrates that the polymer matrix 35 infiltrates the sheet 10 to forma piece of prepreg 33. FIG. 4 shows a cross-section view of prepreg 33with fasteners 31, 37, and 38. A portion of fasteners 31, 37, and 38 canbe at least partially above the polymer matrix 35; other fasteners canbe completely under the surface of the polymer matrix 35. The polymermatrix 35 covers at least some of the fasteners and helps to protectthose fasteners and prevent them from engaging other fasteners on anadjacent sheet. Preferably, the polymer matrix 35 can have at least oneindented portion 36 which is lower than its surrounding area. Theindented portions 36 can be created by means such as cutting or molding.The indented portion 36 further helps to protect the fasteners 31, 37,and 38 and prevent them from engaging other fasteners on an adjacentsheet. The fasteners covered or protected by the polymer matrix 35 canbe exposed when the polymer matrix 35 becomes liquid and flows awayduring the curing process.

FIG. 5 illustrates some methods of generating fasteners 11 and 12. Inone embodiment, a mold or heat iron 39 is configured to press the sheetto form fasteners (e.g., hooks and loops) 11 and 12 of certain shapes,angles, directions, and dimensions. In another embodiment, certainchemical gas or vapor is configured to flow through the sheet surface toform fasteners (e.g., hooks and loops) 11 and 12 of certain shapes,angles, directions, and dimensions. Alternatively, the fasteners 11 and12 can be bonded on, glued on, weld on, compressed on, wrapped on,attached to, disposed on, embedded in, or grown on the sheet or ply. Inaddition, fasteners can be placed on sheets by air or water jet shoot. Acombination of multiple generating methods described herein can also beused.

Fiber sheets can be made by existing textile industry technologies suchas weaving, knitting, wrapping, braiding, stitching, and hook and loop(Velcro®) technologies, or non-weaving technologies (e.g., molding,coating, or needle penetrating). Velcro® loops are generally made byweaving or knitting. Velcro® loops are cut at the desired locations toform Velcro® hooks. Cutting can be achieved by knives, scissors, orother physical, chemical, and mechanical means. For example, laser canbe used to cut loops to form hooks.

FIG. 6A shows a cross-section view of another exemplary sheet 10. Sheet10 is made of at least two layers of fibers 101 and 102. Each fiberlayer can optionally have trans-layer fasteners (e.g., hooks and loops).The at least two layers 101 and 102 can be fastened together by weaving,knitting, and/or stitching. The top view of sheet 10 is shown in FIG.6B.

FIG. 7A shows a cross-section view of yet another exemplary sheet 10.Sheet 10 is made of at least two layers of fibers 101 and 102. Eachfiber layer can optionally have trans-layer fasteners (e.g., hooks andloops). Sheet 10 can optionally have a fiber mat or a substrate 103 asan additional layer. The fiber mat or substrate 103 can be placedoutside the two layers of fibers 101 and 102; alternatively, it can besandwiched between two layers of fibers 101 and 102. The at least twolayers 101 and 102 and the optional fiber mat or substrate layer 103 canbe fastened together by weaving, knitting and/or stitching. The top viewof sheet 10 is showed in FIG. 7B.

FIG. 8 illustrates an exemplary multi-layer multi-axis sheet 10. Sheet10 is made of multiple layers of fibers 101A, 101B, 102A, and 102B. Eachfiber layer can optionally have trans-layer fasteners (e.g., hooks andloops). Fibers in the same layer are approximately lined up in the samedirection or axis. Fibers in different layers can be lined up todifferent directions or axes, forming a multi-layer, multi-axis sheet,as shown in FIGS. 8, 9A, and 9B. The multiple layers 101A, 101B, 102A,and 102B can be bonded together by weaving, knitting, and/or stitching.Sheet 10 can optionally have a matrix material 35 flowed into it to forma prepreg, as shown in FIG. 9A.

In many situations two or more composite structures need to be connectedor bonded. Fasteners at the connection area help to improve theconnection strength. FIG. 10A shows a cross-section view of a firstarticle 100A with fasteners 11 and 12 and a first cover 104A covering atleast a portion of the first article. The first article 100A can be asingle-layer or multi-layer fiber sheet, a composite part, or asubstrate. FIG. 10B shows a cross-section view of a second article 100Bwith fasteners and a second cover 104B covering at least a portion ofthe second article. The second article 100B can also be a single-layeror multi-layer fiber sheet, a composite part, or a substrate. The covers104A and 104B help to protect the covered fasteners 11 and 12 andprevent them from pressing down, engaging, and interlocking each otherduring production processes, such as curing and molding.

The covers 104A and 104B can be made of materials, such as paper,silicone, rubber, polymer, metal wax, paste, powder, etc. The covers canalso be made of mixtures of the aforementioned materials. In oneembodiment, a low melting-point alloy suitable for room temperaturecuring processes is used to cover the fasteners. One example of such analloy is a eutectic alloy, made of about 50% bismuth, about 26.7% lead,about 13.3% tin, and about 10% cadmium by weight, and with a meltingpoint of approximately 70° C. (158° F.). During the curing process, thecovers can be removed by heat and the covered fasteners can then beexposed. In another embodiment, wax and RTV silicone are used to coverthe fasteners. At first, wax is applied as sizing to coat the fasteners,in order to achieve a relatively smooth surface. Then RTV silicone isused to cover the fasteners. During the curing process, RTV siliconecover can be peeled away or be removed by heat or chemical solutions;wax coating can be removed by heat or by chemical solutions.

When the two articles 100A and 100B are ready to be connected, thecovers 104A and 104B can be removed by mechanical, physical and/orchemical means to expose the fasteners, as shown in FIGS. 11A and 11B.The fasteners 11 and 12 on articles 100A and 100B are then engaged andinterlocked together to form a connection/bonding between the firstarticle 100A and the second article 100B, as shown in FIG. 12. Theconnected articles can optionally have a matrix material 35 incorporatedat the connection area for at least one subsequent curing process.

FIG. 13A shows a cross-section view of a first article 200A without anyfastener. The first article 200A can be a single-layer or multi-layerfiber sheet, a composite part, or a substrate. FIG. 13B shows across-section view of a second article 200B without any fastener. Thesecond article 200B can also be a single-layer or multi-layer fibersheet, a composite part, or a substrate. FIG. 13C shows a cross-sectionview of an exemplary fiber sheet 200C with fasteners on both sides. Thefiber sheet 200C can be sandwiched between two articles 200A and 200B atthe connection area, as shown in FIG. 13D. The fasteners on the fibersheet 200C can lock onto the articles 200A and 200B and thus help toimprove the connection strength of articles 200A and 200B.Alternatively, as shown in FIG. 13E, two articles to be connected 300Aand 300B can have their own fasteners at the connection area. The fibersheet 200C can still be sandwiched between two articles 300A and 300B atthe connection area. The fasteners on the fiber sheet 200C can engageand interlock with the fasteners on articles 300A and 300B and thus helpto improve the connection strength of articles 300A and 300B. Theconnected articles can optionally have matrix material 35 incorporatedat the connection area for at least one subsequent curing process.

Referring now to FIG. 14A, a sheet 105 can have upstanding or protrudingstuds 106, windows 107, and/or walls 108. The sheet 105 can be made ofpaper, plastic, or other materials by press molding, injection molding,and/or other means. The upstanding or protruding studs 106 and walls 108can be mounted or welded on to the sheet 105. The upstanding orprotruding studs 106 walls 108 can also be generated on the sheet 105 bymeans such as press molding. The windows 107 can be created by meanssuch as cutting or molding. The sheet 105 can be placed between twosheets with fasteners 10, as shown in FIG. 14B. The upstanding orprotruding studs 106, walls 108, and windows 107 help to create spacesbetween two sheets 10 and protect the fasteners 11 and 12 duringproduction and transportation process, such as layering and rolling.FIG. 14C illustrates that the sheet 105 with upstanding or protrudingstuds 106, walls 108, and windows 107 separates and protects fasteners11 and 12 in a sheet roll 10A.

Automatic handling of fiber sheets has been and is still a big challengein the composite industry. In many situations, the task of lying upfiber sheet is still performed manually, i.e. by hand, mostly due to thelack of effective tools. The present invention describes fiber-sheethandling tools that can be configured to be driven by manual,electrical, hydraulic, magnetic, and/or mechanical forces. Oneembodiment of a fiber-sheet handling tool 108 according to the presentinvention is shown in FIG. 15A. Fiber-sheet handling tool 108 includes abase 115 and a connector 99. The connector 99 is capable of beingcoupled to a control signal and/or a manual, electrical, hydraulic,magnetic, and/or mechanical driving force. The tool 108 has at least onerod 109 that is positioned within a housing unit 114. The rod 109 hasfasteners 11 and 12 on some portion of its surface. The rod 109 isrotatable by manual, electrical, hydraulic, magnetic, and/or mechanicaldriving force. In operation, the tool 108 is positioned adjacent to thesheet 10 with fasteners 11′ and 12′. When the rod 109 is rotated toexpose its fasteners 11 and 12, the fasteners 11 and 12 engage andinterlock with the fasteners 11′ and 12′ on the sheet 10. The engagementand interlocking of fasteners allows the tool 108 to grab the sheet 10.When the rod 109 is rotated to hide its fasteners 11 and 12, thefasteners 11 and 12 disengage and unlock from the fasteners 11′ and 12′of the sheet 10. The disengagement and unlocking of fasteners allows thetool 108 to release the sheet 10.

Another embodiment of a fiber-sheet handling tool 108′ according to thepresent invention is shown in FIG. 15B. Fiber-sheet handling tool 108′includes a base 115′ and a connector 99′. The base 115′ has fasteners 11and 12 on at least some portion of its bottom contact surface. Theconnector 99′ is capable of being coupled to a control signal and/or amanual, electrical, hydraulic, magnetic, and/or mechanical drivingforce. The base 115′ can also optionally have an axis 111 to furthercouple to an additional driving force. The tool 108′ has at least onebar 110 that is positioned within a housing unit 114′. The bar 110 isretractable by manual, electrical, hydraulic, magnetic, and/ormechanical driving force. In operation, the tool 108′ is positionedadjacent to the sheet 10 with fasteners 11′ and 12′. When the bar 110 isretracted to recess within the housing unit 114′, the fasteners 11 and12 of the bottom contact surface of the base 115′ engage and interlockwith the fasteners 11′ and 12′ on the sheet 10. The engagement andinterlocking of fasteners allows the tool 108′ to grab the sheet 10.When the bar 110 is extended to protrude outside the housing unit 114′,the fasteners 11 and 12 of the bottom contact surfaced of the base 115′disengage and unlock from the fasteners 11′ and 12′ of the sheet 10. Thedisengagement and unlocking of fasteners allows the tool 108′ to releasethe sheet 10. In a variation of this embodiment, the base 115′ has nofastener on its bottom contact surface; but the bar 110 has fasteners onat least some portion of its bottom contact surface. In operation, thetool 108′ is positioned adjacent to the sheet 10 with fasteners 11′ and12′. When the bar 110 is extended from the housing unit 114′ to exposeits fasteners, the fasteners of the bar 110 engage and interlock withthe fasteners 11′ and 12′ on the sheet 10. The engagement andinterlocking of fasteners allows the tool 108 to grab the sheet 10. Whenthe bar 110 is retracted to recess into the housing unit 114′, thefasteners of the bar 110 disengage and unlock from the fasteners 11′ and12′ of the sheet 10. The disengagement of fasteners allows the tool 108′to release the sheet 10.

Yet another embodiment of a fiber-sheet handling tool 108″ according tothe present invention is shown in FIG. 15C. Fiber-sheet handling tool108″ includes a base plate 115″, a moving plate 113, and a connector99″. Both the base plate 115″ and the moving plate 113 have at least onepin 112. The connector 99″ is capable of being coupled to a controlsignal and/or a manual, electrical, hydraulic, magnetic, and/ormechanical driving force. Pins 112 are capable to be fit into the gapbetween two sheets 10. The moving plate 113 can be raised or lowered bymanual, electrical, hydraulic, magnetic, and/or mechanical drivingforce. In operation, the tool 108″ is positioned adjacent to sheets 10so that the pins 112 are configured to fit into the gap between twosheets. When the moving plate 113 is raised, the fasteners betweensheets disengage and unlock from each other. The disengagement andunlocking allows the tool 108″ to separate and grab the sheet 10. Whenthe moving plate 113 is lowered, the fasteners between sheets engage andinterlock with each other. The engagement and interlocking of fastenersallows the tool 108″ to release the sheet 10.

The 3-Dimension fiber structures for composites and interfaces have widerange of applications. For one example, a cutting wheel can be at leastpartially made of 3-Dimension fiber structures. One embodiment of such acutting wheel is shown in FIGS. 16A and 16B. In this embodiment, aplurality of sheets 10 with fasteners 11 and 12 are interlockedtogether, providing the cutting wheel with enhanced laminate strength.In addition, the exposed fasteners 11 and 12 on the outermost sheets canhelp to withhold and suppress particles 120 (e.g., sawdust) generatedduring the cutting process, increasing the usage life of the cuttingwheel and associated equipments. The cutting wheel can be manufacturedusing conventional processes, with the exception that the individuallayers are made of sheets with fasteners. For another example, a tirecan be at least partially made of 3-Dimension fiber structures. Oneembodiment of such a tire is shown in FIGS. 20A and 20B. In thisembodiment, a plurality of sheets 10 with fasteners 11 and 12 areinterlocked together. The fasteners 11 and 12 on at least one sheet 10can also penetrate, engage, and interlock with at leas one other layer145 of the tire, such as a fabrics or a net. The engagement andinterlocking can form strong 3-D reinforcements in tires, providingfeatures such as longer usage life, higher puncture-resistance, andstronger interlaminate strength. Sheets 10 and other layers 145 of atire can be made of various materials, such as Kevlar, carbon fiber,glass fiber, steel wire, or other fiber materials. Sheets 10 in tirescan optionally have matrix material 35 incorporated/applied for bonding.

The 3-Dimension fiber structures for composites can also be used tomanufacture structures with internal spaces. FIG. 21 illustrates anexample of such a structure.

Several sheets or substrates 10 are laid together layer-by layer to forma composite panel or block 215 with hollow spaces inside. The fasteners(e.g., hooks and loops) can be configured to engage each other toprovide inter-layer connections and supports. The stack of substrates 10is not fully compressed; and thus, there is hollow space 211 between thesubstrates 10. The fasteners 11 and 12 can act both asconnectors/supports and as spacers between substrates 10 in a compositestructure. The hollow space within the composite panel or block 215helps to improve certain characteristics (e.g., thermal resistance) ofthe composite panel or block 215. Such panel composite panels or blockscan be used in the construction industry, such as to make walls anddoors. Preferably, the top sheet and the bottom sheet have fastenersonly on the inner side of the sheets. Optionally, the top sheet and thebottom sheet do not have fasteners at all. Composite panel 215 can bemanufactured by using a stack of prepreg sheets or by infiltrating the3D stack of sheet 10 preform with resin.

The fasteners on two sides of a sheet are not necessarily of the samelength or same stiffness. FIG. 17A illustrates an exemplary sheet 100with shorter and stiffer fasteners 121 on one side and longer and softerfasteners 122 on the other side. Fibers such as fiberglass and carbonfiber have different bending modulus. A shorter fastener is generallystiffer and harder against bending and buckling under a particularcompression load. When shorter and stiffer fasteners 121 are pressedagainst longer and softer fasteners 122, the shorter and stifferfasteners 121 will normally engage and interlock with the longer andsofter fasteners 122, as shown in FIG. 17B. The shorter and stifferfasteners 121 on a sheet plane 10 can achieve an acute angle 124 leaningtowards a desired direction by optimizing weaving and knittingtechnologies for making Velcro fasteners, towels, etc. Fasteners leaningwith acute angle 124 can also be obtained by applying coating and sizingmaterials 123 at the desired location and direction on the fasteners inorder to sharpen the leaning fasteners. Fasteners leaning with acuteangle help to engage other fasteners on an adjacent sheet. FIGS. 19A and19B are two photos of a prototype, showing fasteners with acute angleengaged and interlocked with each other.

Referring now to FIGS. 18A and 18B, another exemplary process ofgenerating fasteners on a sheet is illustrated. FIG. 18A shows across-section view of an exemplary sheet 100 with at least one opening35. At first, matrix material 35 is applied to the inner walls ofopenings 35. Then, flocking technologies, either via electrical field ormechanical means, is used to run fasteners 130 through openings 35 onsheet 100. Optionally, fasteners 130 can be aligned by a plate or a film131 to achieve a desired height/length above the surface of sheet 100.

The detailed descriptions above in connect with the correspondingfigures are intended to illustrate the present invention, and are notintended to represent the only forms in which the present invention maybe constructed and/or utilized. The descriptions set forth the structureand the sequence of steps for practicing the present invention inconnection. It is to be understood, however, that the same or equivalentstructures and steps may be accomplished by different embodiments thatare also intended to be encompassed within the spirit and scope of theinvention. Accordingly, it is not intended that the invention be limitedexcept by the claims.

It is noted that one or more references are incorporated herein. To theextent that any of the incorporated material is inconsistent with thepresent disclosure, the present disclosure shall control. Furthermore,to the extent necessary, material incorporated by reference hereinshould be disregarded if necessary to preserve the validity of theclaims.

Further, while the description above refers to the invention, thedescription may include more than one invention.

What is claimed is:
 1. A sheet article, comprising: a substrate; aplurality of fasteners on at least a portion of one surface of thesubstrate; and a cover, at least partially covering the plurality offasteners; wherein the cover at least partially protects the pluralityof fasteners and prevents the plurality of fasteners from engaging otherfasteners or pressing down; wherein the covered fasteners can be exposedor the cover can be removed if need.
 2. The sheet article in claim 1,wherein the plurality of fasteners are selected from a group comprisingof hooks, loops, anchor-shape hooks, fish hooks, forks, big heads,arrow-shape hooks, group loops, and group hooks.
 3. The sheet article ofclaim 1, wherein the cover comprising: a second substrate; a pluralityof upstanding or protruding studs or walls on the second substrate;wherein the plurality of upstanding or protruding studs or walls protecta plurality of fasteners in an adjacent sheet.
 4. The sheet article inclaim 2, wherein the hook or loop shape hook is stiffened to a certainlevel so that it can really engage with other hook or loop fasteners ofother sheet article.
 5. The sheet article in claim 1, wherein in orderto stack up the sheet articles, the covers are only on the designedparts of the designed sheet (designed part on the surface sheet); lay upat least three plies of the sheet articles to form a 3D composite,wherein all plies may be fastened by the engaged fasteners on saidpiles, wherein matrix material to bond the at least three plies, whereinsurface side may or may not have fasteners, wherein surface side may ormay not have covers at the designed part.
 6. The sheet article in claim1, wherein sheet article is impregnated with one or more matrixmaterials selected from the group of polymer, resin, metal, ceramic,carbon, glass to obtain a prepreg sheet, lay up at least two saidprepreg plies to get a 3D composite, wherein only surface side may ormay not have covers at the designed part.
 7. The sheet article in claim1, wherein in order to increase the bonding strength of two articles,the cover is removed, insert the sheet article to the interface area oftwo articles when bonding the two articles, wherein the fasteners on thesheet article will extend into the bodies of two bonding articles toincrease interface strength, wherein the fasteners on the sheet articlewill interlock with the fasteners of two bonding articles if they havefasteners themselves.
 8. The sheet article in claim 1, wherein saidsubstrate is comprised of plurality of fiber sheet plied contiguously,wherein said plurality fiber sheet are mechanically fastened together.9. The sheet article in claim 8, wherein said fibers in the same sheetcan be lined up to a same direction or to different directions forming amulti-layer multi-axis sheet.
 10. The sheet article in claim 1, whereinin order to stack up the sheet articles, the covers are only on thedesigned parts of the designed sheet (designed part on the surfacesheet); lay up at least two plies of the sheet articles to form a 3Dcomposite wherein all plies may be connected and supported by thefasteners on said piles; wherein matrix material to infiltrate at leastpartial of the plies and fasteners, wherein said plies are not fullytouched and there are hollow spaces between plies, wherein surface sidemay or may not have fasteners, wherein surface side may or may not havecovers at the designed part.
 11. The sheet article in claim 1, whereinsheet articles have gap between two sheet articles to be fit in by pinsof fiber sheet handling tool, wherein pins can grab and separate thesheet article.
 12. The sheet article in claim 1, wherein fasteners canlean with acute angle at desired location and direction.
 13. The sheetarticle in claim 1, wherein substrate have matrix material at innerwalls of openings, wherein fasteners can be aligned through openings.14. A method of using fastener cover on a sheet, comprising the stepsof: applying a covering material to at least one fastener on the sheetto protect the at least one fastener; and removing the cover materialduring a bonding process to expose the at least one fastener.
 15. Themethod of claim 14, wherein the applying step further comprises the stepof: applying a sizing or a coating material to coat the at least onefastener.
 16. A tire or cutting wheel, comprising: a plurality ofsheets; and a plurality of fasteners on at least one of the plurality ofsheets; wherein the plurality of fasteners on adjacent sheets areinterlocked.
 17. The cutting wheel in claim 16, wherein the plurality offasteners in the tire or cutting wheel withhold particles againstwearing during cutting.